Catharus guttatus

This species formerly was placed in genus Hylocichla (AOU 1983). Systematics are complex and have little consensus. Several subspecies are recognized by various authors. The American Ornithologists' Union (1957) and Ripley (1964) recognized eight subspecies, Aldrich (1968) recognized 10 subspecies, and Phillips (1991) recognized 13 (see Jones and Donovan 1996). Subspecies vary morphologically, especially in wing, tail, and tarsus length, and plumage coloration; bill length increases from north to south of range, tarsus length decreases from north to south (Aldrich 1968). Three generally recognizable groups include birds occurring east of the Rocky Mountains, central Alaska south through the Sierra Nevada and Rocky Mountains, and west and north of the Sierra Nevada-Cascade ranges along the Pacific coast (Lane and Jaramillo 2000).

Widespread, abundant, and secure.

Breeding range extends from western and central Alaska across southern Mackenzie to southern Labrador and Newfoundland, south to southern Alaska, in the mountains to southern and eastern California, southern Nevada, central and southeastern Arizona, southern New Mexico, and western Texas; east of the Rockies to southwestern and central Alberta, central Saskatchewan, northern Minnesota, northeastern Ohio, western Virginia, western Maryland, southern New Jersey, and southern New York; also isolated breeding population in Black Hills, South Dakota (AOU 1998). Breeding also occurs in the Sierra San Pedro Martir, Baja California (Erickson and Wurster 1998). Nonbreeding range extends from southern British Columbia, northern U.S., southern Ontario and New England, south to southern Baja California, through Mexico to Guatemala and El Salvador, southern Texas, Gulf Coast, southern Florida, and the northern Bahamas (AOU 1998).

This species is represented by a large number of occurrences (subpopulations).

Potential threats include human-caused and natural habitat alteration or loss, effects of human intrusion, and natural causes of mortality such as predation and severe weather events. However, on a range-wide scale, this species is not significantly threatened.

Changes in abundance have been noted in response to various tree removal practices. Some researchers suggest that Hermit Thrush populations are equally stable on both logged and unlogged habitats (Webb et al. 1977, Medin 1985) and that density and productivity are higher in younger stands (Rangen et al. 2000). Others suggest that breeding densities are higher in unlogged habitats (Franzreb and Ohmart 1978, Medin and Booth 1989, Jones and Donovan 1996, Hanowski et al. 2003).

Hermit Thrush densities have decreased following wildfires. Declines resulted both immediately (Apfelbaum and Haney 1981) and several years post- burn (8 years later; see sources in Jones and Donovan 1996).

Habitat fragmentation and the resultant increase in edge habitats may negatively affect nesting success due to increased predator abundance and activity along edges (Manolis et al. 2002). Hames (1999) reported that as forest habitat fragmentation increased, nesting attempts decreased throughout the species' North American range.

Martin and Roper (1988, in Jones and Donovan 1996) suggested that disturbance by researchers did not impact thrush nesting behavior or success in Arizona, but Gutzwiller and Anderson (1999) reported that low levels of human intrusion increased displacement of thrushes and resulted in lower abundance than prior to intrusion events in the Snowy Mountains, Wyoming.